Differential pressure sensor: Error code P2453 despite new sensor

Hello everyone,

A few weeks ago, the problems started with a fault code from the differential pressure sensor indicating "short circuit to positive." A new differential pressure sensor was then installed by an (independent) workshop, and the error codes were cleared. However, after 2 days, the same two error codes reappeared.
7347 - Diesel particulate filter differential pressure sensor.
P2453 00 [173] - implausible signal.
and
7346 - Diesel particulate filter differential pressure sensor.
P2453 00 [237] - implausible signal.
(where the second error message always indicates an invalid date and an implausible speed of 255 km/h. And why are there always two almost identical messages??)

The workshop is at a loss, and the pressure hoses will be checked again during the service appointment in two weeks.
I registered the new sensor using VCDS through the "Adaptation" menu, but the error message keeps appearing.
What's raising my suspicion: according to the log, the new sensor has an offset of -75 hPa, but immediately after the adjustment, it shows 0 hPa.
Do the sensors really have such a wide range of variation?
Could the sensor be malfunctioning again?

I'm attaching a log from my Roomster 1.6 (105 hp), maybe someone can comment on it.

Best regards!

Have you ever logged and examined the differential pressures? It would be useful to do this while running the engine at full load, between 1,500 and 4,000 rpm, in a high gear. Then you can check if any unusual differential pressures are being measured.

Greetings.
Guste.

Okay, I'll try to figure out how to do this in a way that's somewhat compliant with traffic regulations. I don't have a co-pilot who can operate the laptop for me.

udiederichs wrote:

I'll try to figure out how to do this in a way that's somewhat compliant with traffic regulations.

I don't have a co-pilot who could just operate the laptop. }
You can easily start the logging process with the laptop while the vehicle is stationary, and then you can take your test drive at your leisure while the data is being recorded. No button presses on the laptop are required during this process.

If necessary, you can delete the irrelevant lines at the beginning of the test run later in the log. However, you can also simply leave them in. Later, the log clearly shows how the differential pressure increases over time, and how the speed gradually increases (please record at least the speed and differential pressure when logging).

Please do not use the laptop while driving.

Greetings.
Guste.

Okay, I logged the drive home today. I selected measurement channels in VCDS under "advanced measurement channels" (hopefully meaningful ones, I can only guess at the meaning of some of the channel abbreviations).

The CSV file can be opened and visualized using KDataScope.

If I've selected inappropriate channels, please let me know which ones are better.

Thank you!

udiederichs wrote:

Okay, I logged the drive home today. I selected measurement channels in VCDS under "advanced measurement channels" (hopefully meaningful ones; I can only guess at the meaning of some of the channel abbreviations). The CSV file can be opened and visualized using KDataScope. If I've selected inappropriate channels, please let me know which ones are better. Dankeschön!

Hello,

Logging values that are constantly at 0 is pointless, as is the vehicle speed. What matters is the engine load, which includes the engine speed and the current fuel injection amount.
Für den Differenzdruck gibt es sicher auch Messwerte die sinnvolle Daten liefern.

Are the hoses connected to the differential pressure sensor not clogged? If two are connected and not just one... is the correct differential pressure sensor installed?

Best regards, Rainer.

Constant zero sequences are "meaningless," no question about that, but I'm still a bit unfamiliar with the meaning of the measurement channels (not all of them are self-explanatory to me).

I have more time on the weekend, so I can delve into it more thoroughly then.

Swapped the hoses: I'll test that. I can't offer the control unit any more nonsensical data like I have been.

We'll see...

Result: Hoses are okay and not blocked. The cause is the differential pressure sensor. The "new" sensor is a very cheap part and is already defective. There is no manufacturer printed on it, and it doesn't have any of the common OE part numbers. It smells strongly of melted plastic.
Purchased (50€) and installed in an independent workshop. I will return the sensor tomorrow.
I purchased a new Bosch sensor from an online retailer and installed it today. During the first measurement, it already provided plausible (positive) values. I then initiated a service regeneration while driving and burned off the soot (the temperature briefly rose to 780°).

Let's hope that this issue is now resolved.

Best regards!

Thank you for your feedback! ❤️